Can Fasting Be Part of a Diabetes Meal Plan?

There's been a lot of buzz in the media recently promoting the benefits of intermittent fasting—skipping a meal or limiting daily calories on some days—as a means to lose weight, reduce cardiovascular risk, improve insulin sensitivity, and decrease inflammation and the risk of type 2 diabetes. Fasting goes against the mainstream approach of eating regular meals to keep blood sugars stable. Because weight loss is an overwhelming issue with type 2 (and a difficult one to master), it's worth considering whether fasting is a safe and reasonable option.

Studies have shown that restricting calories can increase the life span of certain animals by as much as 50 percent. Fasting is not a new concept. For centuries, many religions have used fasting for physical and spiritual benefits. We evolved from ancestors who did not have continuous access to food; the norm was feast or famine. It has been suggested that perhaps our genes are designed to respond better to sporadic eating, instead of eating throughout the day, because it mimics the stress and shock that our ancestors experienced, which in turn keep the body healthier and tougher.

A recent review in the British Journal of Diabetes and Vascular Disease evaluated various approaches to intermittent fasting. The researchers found that overweight people with type 2 diabetes who fasted intermittently lost as much or more weight than those who cut calories on a daily basis. There are several approaches to intermittent fasting, but the basic idea is to alternate days of eating normally with days of restricted calorie consumption (500 to 600 calories per day). One example is to choose two nonconsecutive days each week as fasting days along with five days of eating normally. Another approach is to restrict eating to a specific period each fasting day, such as an eight-hour window of time. For example, all calories would be consumed from 12 p.m. to 8 p.m. The rationale for this approach is that it takes about six to eight hours to burn the carbohydrate stored in your body as glycogen. After the stores are drained—and until more food is consumed—the body is primed to burn fat as its primary fuel.

Intermittent fasting is not for the faint of heart, yet it is doable. Unlike total fasting, you simply eat less on fast days. Many study participants reported that after the initial hunger and discomfort of calorie restriction, their hunger subsided and cravings diminished, and they experienced a sense of alertness, a high energy level, and improved mood.

There is good evidence that intermittent fasting may be useful in preventing type 2 diabetes, but how does this translate to people living with diabetes? As you may know, anyone who takes insulin or uses sulfonylureas will risk hypoglycemia when fasting. Discuss this with your health care provider if you are considering intermittent fasting as a weight-loss strategy.